Study On Plasma Enhanced Atomic Layer Deposition In The Thin Film Deposition Of Copper Interconnect

With the rapid development of integrated circuits(IC), copper interconnect technology will be put forward more requirements. Nowadays, the complex three-dimensional surface depositions of high quality copper seed layer as well as the preparation of high efficient diffusion barrier layer become the urgent problems in the microelectronics industry. Atomic layer deposition technique,based on the principle of the surface self-limiting saturated chemical adsorption reaction, will become the future preferrable process for the preparation of conformal ultrathin films. Duo to the fact that copper atoms will easily aggregate and react with silicon at high temperature and interconnection devices are unbearable at high deposition temperature, the development of low-temperature atomic layer deposition technique becomes necessary in the interconnect industry.As well known plasma technology can reduce the reaction tempperature and increase the surface reactive sites, which is preferred for using in the low temperature atomic layer deposition.This thesis based on atomic layer deposition technique, using Cu(amd) and Mn(tBu2DAD) 2 as copper and manganese precursors, respectively, presents the metal copper film and manganese nitride film depositions in the low temperature condition. The achievements are:(1) PA-ALD Cu films have been deposited with copper amidine precursor for the first time at the low temperature plasma. When the deposition temperature was 50 °C, the input power was 80 W, the ALD cycle for the copper precursor/purge/hydrogen plasma/purge was 5/10/10/10 s, a high purity, conformal, continuous, smooth copper film could be obtained inside the silicon trench with the aspect ratio of 10:1, and deposition rate of this process was 0.071 nm/cycle. The in-situ diagnostic measurements, the time-resolved emission spectroscopy and quartz crystal microbalance technology, showed that Cu(amd) chemical adsorption on the surface partially decomposed to form isopropyl and N-isopropyl acetamide at 50 °C. However, atomic hydrogen in the plasma could hydrogenate Cu(amd), isopropyl and N-isopropyl acetamide and the forming volatile byproducts hydrogen separated away, leaving the copper on the substrate.(2) PA-ALD manganese nitride thin films have been produced for the first time. The preliminary study showed that η-Mn3N2 film could be obtained at certain condition when the deposition temperature was 250 °C or 300 °C, the input power was 100 W, the ALD cycle for themanganese precursor/purge/hydrogen plasma/purge was 5/15/10/15 s. The deposition rate was0.078 nm/cycle at 250 °C. However, when 40 sccm ammonia and 20 sccm hydrogen were mixed,η-Mn3N2 film and metal manganese film could be formed at 100 W and 200 W, respectively.